**5.3 TOTAL HEAD**

Each term of the Bernoulli’s equation represent the dimension of length i.e., in 5.1. it is meter. Left hand side i.e.,(p / p g + v^{2} / 2 g + z) is called the total head.

**5.4 VELOCITY HEAD**

In equation (5.3), v is the velocity and ( v^{2} / 2 g) is called the velocity head.

**5.5 PRESSURE HEAD**

In equation (5.3), p is the pressure and (:g ) is called the pressure head.

**5.6 DATUM OR POTENTIAL HEAD**

In equation (5.3), z is called the datum head or potential head.

**Note :** All the head is nothing but energy per unit weight.

**5.7 ASSUMPTIONS MADE FOR DERIVING BERNOULLI’S EQUATION**

Following are some Assumptions made for deriving Bernoulli’s equation:

(i) The flow is incompressible.

(ii) The flow is steady.

(iii) The fluid is non viscous (ยต. = 0)

(iv) The flow is irrotational.